Subannular Sealing for Paravalvular Leak Protection

ABSTRACT

A prosthetic heart valve for replacing a native valve includes a collapsible and expandable stent extending between a proximal end and a distal end. The stent includes an annulus section adjacent the proximal end and having a first diameter, a plurality of first struts forming cells, and a plurality of second struts connected to the annulus section and forming a plurality of deflecting cells expandable to define a second diameter larger than the first diameter. A valve assembly is disposed within the stent and a cuff is coupled to the stent and covers the plurality of deflecting cells.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 15/310,915, filed Nov. 14, 2016, which is a national phase entryunder 35 U.S.C. § 371 of International Application No. PCT/US2015/030358filed May 12, 2015, published in English, which claims the benefit ofthe filing date of U.S. Provisional Patent Application No. 61/994,271filed May 16, 2014, the disclosures of which are all hereby incorporatedherein by reference.

The present disclosure relates in general to heart valve replacementand, in particular, to collapsible prosthetic heart valves. Moreparticularly, the present disclosure relates to devices and methods forpositioning and sealing collapsible prosthetic heart valves within anative valve annulus.

Prosthetic heart valves that are collapsible to a relatively smallcircumferential size can be delivered into a patient less invasivelythan valves that are not collapsible. For example, a collapsible valvemay be delivered into a patient via a tube-like delivery apparatus suchas a catheter, a trocar, a laparoscopic instrument, or the like. Thiscollapsibility can avoid the need for a more invasive procedure such asfull open-chest, open-heart surgery.

Collapsible prosthetic heart valves typically take the form of a valvestructure mounted on a stent. There are two common types of stents onwhich the valve structures are mounted: a self-expanding stent or aballoon-expandable stent. To place such valves into a delivery apparatusand ultimately into a patient, the valve must first be collapsed orcrimped to reduce its circumferential size.

When a collapsed prosthetic valve has reached the desired implant sitein the patient (e.g., at or near the annulus of the patient's heartvalve that is to be replaced by the prosthetic valve), the prostheticvalve can be deployed or released from the delivery apparatus andre-expanded to full operating size. For balloon-expandable valves, thisgenerally involves releasing the entire valve, and then expanding aballoon positioned within the valve stent. For self-expanding valves, onthe other hand, the stent automatically expands as the sheath coveringthe valve is withdrawn.

SUMMARY OF THE INVENTION

In some embodiments, a prosthetic heart valve for replacing a nativevalve includes a collapsible and expandable stent extending between aproximal end and a distal end. The stent includes an annulus sectionadjacent the proximal end and having a first diameter, a plurality offirst struts forming cells, and a plurality of second struts connectedto the annulus section and forming a plurality of deflecting cellsexpandable to define a second diameter larger than the first diameter. Avalve assembly is disposed within the stent and a cuff is coupled to thestent and covers the plurality of deflecting cells.

In some embodiments, a prosthetic heart valve for replacing a nativevalve includes a collapsible and expandable stent extending between aproximal end and a distal end and an annulus section adjacent theproximal end and having a first diameter. The stent includes a pluralityof first struts forming cells, and a plurality of projecting strutsjoined to proximal-most cells, each of the projecting struts having afree end and an attached end joined to an intersection of first struts.A valve assembly is disposed within the stent and a cuff is coupled tothe stent and covering the projecting struts.

In some embodiments, a prosthetic heart valve for replacing a nativeheart valve includes a collapsible and expandable stent having proximaland distal ends, the stent including an annulus section adjacent theproximal end, the annulus section having a first expanded diameter and afirst radial spring constant. The stent further includes a plurality ofdeflecting features which project outwardly from the annulus sectionwhen the stent is in an expanded condition, the deflection featureshaving a lower radial spring constant than the first section. A valve isdisposed within the annulus section distal to the deflection features,the valve being operative to permit flow toward the distal end of thestent and to substantially block flow toward the proximal end of thestent. The heart valve further includes a cuff, a portion of the cuffbeing coupled to the deflection features.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments in accordance with the present disclosure will nowbe described with reference to the appended drawings. It is to beappreciated that these drawings depict only some embodiments and aretherefore not to be considered limiting of its scope.

FIG. 1 is a side elevational view of a conventional prosthetic heartvalve;

FIG. 2 is a highly schematic cross-sectional view taken along line A-Aof FIG. 1 and showing the prosthetic heart valve disposed within anative valve annulus;

FIG. 3A is a highly schematic side view of one embodiment of a heartvalve having projecting struts intended to fill irregularities betweenthe heart valve and the native valve annulus;

FIGS. 3B is a fragmentary view of an enlarged section of the portionindicated in FIG. 3A;

FIG. 3C is a developed view of the stent of the heart valve of FIG. 3Ain the collapsed configuration;

FIGS. 3D is a fragmentary view of an enlarged section of the portionindicated in FIG. 3C;

FIGS. 3E is a schematic representation of the attachment angle of theprojecting struts of FIG. 3A;

FIGS. 4A-D are highly schematic side views of one method of deliveringand deploying the heart valve of FIG. 3A within the native valveannulus;

FIG. 5 is a highly schematic side view of another variation of a heartvalve having projecting struts intended to fill irregularities betweenthe heart valve and the native valve annulus;

FIG. 6A is a side view of a stent having a sealing row of deflectingcells;

FIG. 6B is a highly schematic partial cross-sectional view of theannulus section of the stent of FIG. 6A;

FIG. 6C is a schematic partial side view of the stent of FIG. 6A;

FIG. 6D are schematic cross-sectional views of the struts of FIG. 6A;

FIG. 7A is a side view of another variation of a stent having a sealingrow of deflecting cells;

FIG. 7B is a highly schematic partial cross-sectional view of theannulus section of the stent of FIG. 7A;

FIG. 7C is a schematic partial side view of the stent of FIG. 7A;

FIG. 8A is a side view of another variation of a stent having a sealingrow of deflecting cells;

FIG. 8B is a highly schematic partial cross-sectional view of theannulus section of the stent of FIG. 8A;

FIG. 8C is a schematic partial side view of the stent of FIG. 8A;

FIGS. 9A and 9B are highly schematic cross-sectional and developed viewsof portions of a heart valve having an external cuff;

FIGS. 10A and 10B are highly schematic cross-sectional and developedviews of portions of a heart valve having a two-layered external cuff;

FIGS. 11A and 11B are highly schematic cross-sectional and developedviews of portions of a heart valve having a cuff including an upperluminal portion and a lower abluminal portion;

FIGS. 12A and 12B are highly schematic cross-sectional and developedviews of portions of a heart valve having a cuff wrapped around thestent from the luminal surface to the abluminal surface; and

FIG. 13 is a highly schematic cross-sectional view of a heart valvehaving deflecting cells disposed within a native valve annulus.

DETAILED DESCRIPTION

Inaccurate deployment and anchoring may result in the leakage of bloodbetween the implanted heart valve and the native valve annulus, commonlyreferred to as paravalvular leakage (also known as “perivalvularleakage”). In aortic valves, this leakage enables blood to flow from theaorta back into the left ventricle, reducing cardiac efficiency andputting a greater strain on the heart muscle. Additionally,calcification of the aortic valve and/or anatomical variations from onepatient to another may affect performance and the interaction betweenthe implanted valve and the calcified tissue is believed to be relevantto leakage, as will be outlined below. There is a need for furtherimprovements to the devices, systems, and methods for positioning andsealing collapsible prosthetic heart valves. Specifically, there is aneed for further improvements to the devices, systems, and methods foraccurately implanting a prosthetic heart valve. Among other advantages,the present disclosure may address one or more of these needs.

As used herein, the terms “proximal” and “distal” when used inconnection with a prosthetic heart valve, refer to the inflow andoutflow ends, respectively, of the heart valve corresponding to naturalcirculation of blood through a healthy heart. When used in connectionwith devices for delivering a prosthetic heart valve or other medicaldevice into a patient, the terms “trailing” and “leading” are to betaken as relative to the user of the delivery devices. “Trailing” is tobe understood as relatively close to the user, and “leading” is to beunderstood as relatively farther away from the user.

The sealing features of the present disclosure may be used in connectionwith collapsible prosthetic heart valves. FIG. 1 shows one suchcollapsible stent-supported prosthetic heart valve 100 including a stent102 and a valve assembly 104 as is known in the art. Prosthetic heartvalve 100 is designed to replace a native tricuspid valve of a patient,such as a native aortic valve. It should be noted that while theembodiments discussed herein relate predominantly to prosthetic aorticvalves having a stent with a shape as illustrated in FIG. 1, the valvecould be a bicuspid valve, such as the mitral valve, and the stent couldhave different shapes, such as a flared or conical annulus section, aless-bulbous aortic section, and the like, and a differently shapedtransition section.

Prosthetic heart valve 100 (FIG. 1) includes expandable stent 102 whichmay be formed from biocompatible materials that are capable ofself-expansion, such as, for example, shape memory alloys, such as thenickel-titanium alloy known as “Nitinol” or other suitable metals orpolymers. Stent 102 extends from proximal or annulus end 130 to distalor aortic end 132, and includes annulus section 140 adjacent proximalend 130, transition section 141 and aortic section 142 adjacent distalend 132. Annulus section 140 may have a relatively small cross-sectionin the expanded configuration, while aortic section 142 may have arelatively large cross-section in the expanded configuration.Preferably, annulus section 140 is in the form of a cylinder having asubstantially constant diameter along its length. Transition section 141may taper outwardly from annulus section 140 to aortic section 142. Eachof the sections of stent 102 includes a plurality of struts 160 formingcells 162 connected to one another in one or more annular rows aroundthe stent. For example, as shown in FIG. 1, annulus section 140 may havetwo annular rows of complete cells 162 and aortic section 142 andtransition section 141 may each have one or more annular rows of partialcells 162. Cells 162 in aortic section 142 may be larger than cells 162in annulus section 140. The larger cells in aortic section 142 betterenable prosthetic valve 100 to be positioned in the native valve annuluswithout the stent structure interfering with blood flow to the coronaryarteries.

Stent 102 may include one or more retaining elements 168 at distal end132 thereof, retaining elements 168 being sized and shaped to cooperatewith female retaining structures (not shown) provided on a deploymentdevice. The engagement of retaining elements 168 with the femaleretaining structures on the deployment device helps maintain prostheticheart valve 100 in assembled relationship with the deployment device,minimizes longitudinal movement of the prosthetic heart valve relativeto the deployment device during unsheathing or resheathing procedures,and helps prevent rotation of the prosthetic heart valve relative to thedeployment device as the deployment device is advanced to the targetlocation and the heart valve deployed.

Prosthetic heart valve 100 includes valve assembly 104 preferablysecured to stent 102 in annulus section 140. Valve assembly 104 includescuff 176 and a plurality of leaflets 178 which collectively function asa one-way valve by coapting with one another. As a prosthetic aorticvalve, valve 100 has three leaflets 178. However, it will be appreciatedthat other prosthetic heart valves with which the sealing portions ofthe present disclosure may be used may have a greater or lesser numberof leaflets.

Although cuff 176 is shown in FIG. 1 as being disposed on the luminal orinner surface of annulus section 140, it is contemplated that cuff 176may be disposed on the abluminal or outer surface of annulus section 140or may cover all or part of either or both of the luminal and abluminalsurfaces. Both cuff 176 and leaflets 178 may be wholly or partly formedof any suitable biological material or polymer such as, for example,Polyethylene terephthalate (PET), ultra-high-molecular-weightpolyethylene (UHMWPE), or polytetrafluoroethylene (PTFE).

Leaflets 178 may be attached along lower belly portions to cells 162 ofstent 102, with the commissure between adjacent leaflets 178 attached tocommissure features 166. As can be seen in FIG. 1, each commissurefeature 166 may lie at the intersection of four cells 162, two of thecells being adjacent one another in the same annular row, and the othertwo cells being in different annular rows and lying in end-to-endrelationship. Preferably, commissure features 166 are positionedentirely within annulus section 140 or at the juncture of annulussection 140 and transition section 141. Commissure features 166 mayinclude one or more eyelets which facilitate the suturing of the leafletcommissure to stent 102.

Prosthetic heart valve 100 may be used to replace a native aortic valve,a surgical heart valve or a heart valve that has undergone a surgicalprocedure. Prosthetic heart valve 100 may be delivered to the desiredsite (e.g., near the native aortic annulus) using any suitable deliverydevice. During delivery, prosthetic heart valve 100 is disposed insidethe delivery device in the collapsed configuration. The delivery devicemay be introduced into a patient using a transfemoral, transaortic,transsubclavian, transapical, transseptal or any other percutaneousapproach. Once the delivery device has reached the target site, the usermay deploy prosthetic heart valve 100. Upon deployment, prosthetic heartvalve 100 expands so that annulus section 140 is in secure engagementwithin the native aortic annulus. When prosthetic heart valve 100 isproperly positioned inside the heart, it works as a one-way valve,allowing blood to flow from the left ventricle of the heart to theaorta, and preventing blood from flowing in the opposite direction.

FIG. 2 is a highly schematic cross-sectional illustration of prostheticheart valve 100 disposed within native valve annulus 250. As seen in thefigure, valve assembly 104 has a substantially circular cross-sectionwhich is disposed within the non-circular native valve annulus 250. Itwill be understood that while prosthetic heart valve 100 is shown havinga circular cross-section for the sake of clarity, certain portions willdeflect to accommodate the geometry in the anatomy. Additionally, heartvalve 100 may include an elliptical or D-shaped cross-section for use inmitral, tricuspid, or diseased bicuspid valve applications. At certainlocations around the perimeter of heart valve 100, gaps 200 form betweenheart valve 100 and native valve annulus 250. Blood flowing throughthese gaps and past valve assembly 104 of prosthetic heart valve 100 cancause regurgitation and other inefficiencies which reduce cardiacperformance. Such improper fitment may be due to suboptimal native valveannulus geometry due, for example, to calcification of native valveannulus 250 or to irregularities in unresected native leaflets.

FIG. 3A illustrates one embodiment of heart valve 300 intended to fillthe irregularities between the heart valve and native valve annulus 250shown in FIG. 2. Heart valve 300 extends between proximal end 302 anddistal end 304, and may generally include stent 306 and valve assembly308 having a plurality of leaflets 310 and cuff 312. Heart valve 300 maybe formed of any of the materials and in any of the configurationsdescribed above with reference to FIG. 1.

Stent 306 may include a plurality of struts 320 and extend from proximalor annulus end 302 of heart valve 300 to distal or aortic end 304. Stent306 may include annulus section 340 adjacent proximal end 302, aorticsection 342 adjacent distal end 304, and transition section 341 betweenannulus section 340 and aortic section 342. Commissure features 345 maybe positioned entirely within annulus section 340 or at the juncture ofannulus section 340 and transition section 341 as shown.

At distal end 304, certain struts 320 may terminate in retainingelements 321. Additionally, struts 320 may come together to form cells322 connected to one another in one or more annular rows around thestent. Specifically cells 322 are diamond-shaped and include fourintersections or nodes of struts 320. The functional features of valve300 may be generally similar to the corresponding features of valve 100discussed above. Adjacent the proximal-most full row of cells 322additional features are included to reduce paravalvular leakage. Thesefeatures are best described with reference to the enlargement shown inFIG. 3B. As shown, cells 322 a and 322 b are disposed adjacent to oneanother and share a common node 331 a (e.g., struts 320 a of cell 322 aand 320 b of adjacent cell 322 b intersect at node 331 a). A pluralityof projecting struts 330 are provided, each projecting strut 330including an attached end coupled to node 331 a and a free end havingeyelet 332. In this example, two projecting struts 330 extend from eachnode 331 a. It will be understood, however, that a single projectingstrut 330 or more than two projecting struts 330 may extend from eachnode. Additionally, projecting struts 330 need not extend from each node331, but may be extend from less than all of the nodes. For example,projecting struts 330 may extend from alternating nodes around thecircumference of heart valve 300.

Projected struts 330 may be biased to extend radially outward to definea diameter greater than the diameter of annulus section 340. In additionto the biasing, cuff 312 may be attached to eyelets 332 and expandradially outward with projecting struts 330 to better seal heart valve300 within the native valve annulus.

In order to better appreciate the attachment and placement of projectingstruts 330, stent 306 is shown in FIG. 3C in its collapsedconfiguration. A portion of the collapsed stent is shown in detail on anenlarged scaled in FIG. 3D. For the sake of clarity, valve assembly 308is not shown in this figure. In the collapsed configuration of stent306, cells 322 may be substantially stadium-shaped (e.g., having twoparallel sides and two semi-circles connecting the parallel sides). Thiscollapsed shape, however, may be modified as desired and may also changebased on the amount of compression applied to the stent. In the expandedconfiguration of stent 306, cell 322 may shorten in the length directionof stent 306 between proximal end 302 and distal end 304, and struts 320may generally form a diamond shape (FIG. 3A).

Projecting struts 330 may extend from first attached ends 335 a, wherestruts 320 a and 320 c meet (e.g., node 331 a), to free ends 335 b.Attached ends 335 a may be affixed to stent 306 by welding, adhesive, orany other suitable technique known in the art. Moreover, instead ofbeing separately formed and affixed to stent 306 at nodes 331 a,projecting struts 330 may be integrally formed with stent 306, such asby laser cutting both stent 306 and projecting struts 330 from the sametube.

As seen in FIG. 3E, in the collapsed configuration, projecting struts330 may be substantially parallel to longitudinal axis Y of heart valve300 at position P1. As heart valve 300 expands, projecting struts 330begin to angle outwardly, forming an angle α with longitudinal axis Y ofheart valve 300 to position P2. In at least some examples, angle α isbetween about 15 degrees and about 35 degrees. It will be understoodthat angle α may, however, be greater than 35 degrees or less than 15degrees as desired. Stent 306 may be formed such that struts 320 andprojecting struts 330 return to a predetermined angled configuration inthe fully expanded configuration due, for example, to elasticity of theprojecting struts (e.g., when no external forces are applied thereto).When projecting struts 330 project outwardly to position P2 on theexpansion of heart valve 300, they form protuberances in cuff 312 tohelp seal heart valve 300 within the native valve annulus. Additionally,though projecting struts 330 may be configured to deflect to a givenangle when unconstrained (e.g., 35 degrees), it will be understood thatin use, projecting struts 330 may outwardly deflect to an angle lessthan the maximum unconstrained angle (e.g., 20 degrees) due to thepresence of calcium nodule or other anatomical structure. Moreover, inthis configuration, projecting struts 330 may be capable of independentmovement so that a first projecting struts 330 is capable of deflectingoutwardly to a first angle α, while a second projecting strut 330deflects to a smaller extent to accommodate a calcium nodule or otheranatomical structure. Thus, it will be understood that cuff 312 need notexpand to a circular circumference at projecting struts 330.

A method of delivering and implanting heart valve 300 will now bedescribed with reference to FIGS. 4A-D. A delivery system 400 may beused to deliver and deploy heart valve 300 in native valve annulus 250,and may generally include sheath 410, shaft 420, atraumatic tip 430 andhub 440. Sheath 410 may be slidable relative to shaft 420. Heart valve300, including stent 306, valve assembly 308 and projecting struts 330,may be disposed within sheath 410 about shaft 420 (FIG. 4A). Hub 440 maybe coupled to shaft 420 and configured to mate with retaining elements321 of heart valve 300. Projecting struts 330 of heart valve 300 may besubstantially parallel to the longitudinal axis of sheath 410, duringdelivery. Specifically, though projecting struts 330 are configured toreturn to their angled configuration, they may be kept substantiallyparallel by being constrained within sheath 410. By doing so, heartvalve 300 may be delivered to the native valve annulus using deliverysystem 400 without increasing the radius of sheath 410, avoiding theneed to increase the crimp profile of the heart valve within deliverysystem 400 (i.e., the diameter of the heart valve in the collapsedcondition). A large delivery system may be incapable of being passedthrough the patient's vasculature, while a delivery system having aheart valve with a smaller crimp profile may be easier to navigatethrough a patient's body and may also reduce the length of theimplantation procedure. In the example shown in FIGS. 4A-D, deliverysystem 400 is delivered from the aorta toward the left ventricle asindicated by arrow 51. If heart valve 300 or delivery system 400includes echogenic materials, such materials may be used to guidedelivery system 400 to the appropriate position using the assistance ofthree-dimensional echocardiography to visualize heart valve 300 withinthe patient. Alternative visualization techniques known in the art arealso contemplated herein.

When delivery system 400 has reached the proper location (e.g.,atraumatic tip 430 is just past native valve annulus 250), atraumatictip 430 may be decoupled from sheath 410 (FIG. 4B). Sheath 410 may thenbe retracted in the direction of arrow S2 toward the aorta. With sheath410 slightly retracted, heart valve 300 begins to emerge from thesheath. As sheath 410 is further retracted in the direction of arrow S2,more of heart valve 300 is exposed until annulus section 340 is fullyexposed and projecting struts 330 begin to protrude outwardly (FIGS.4B-C). Thus, sheath 410 may be retracted until heart valve 300 is freeto self-expand within native valve annulus 250. While heart valve 300 ispartially deployed (e.g., a portion of heart valve 300 is outside sheath410, but heart valve 300 is not fully detached from delivery system400), if it appears that heart valve 300 needs to be recaptured andredeployed due to, for example, improper positioning or orientation,sheath 410 may be slid over shaft 420 in the direction of arrow 51 torecapture heart valve 300 within sheath 410. During recapture, sheath410 may push against projecting struts 330 to straighten them to theparallel configuration shown in FIG. 4A. This process may be repeateduntil heart valve 300 is properly positioned and deployed within nativevalve annulus 250.

After sheath 410 has been fully retracted to expose heart valve 300,projecting struts 330, now in their angled configuration, push cuff 312outwardly against native valve annulus 250. The cuff occludes gaps 200between heart valve 300 and native valve annulus 250, thereby reducingor eliminating the amount of blood that passes around heart valve 300through gaps 200 (FIG. 4D). Retaining elements 321 of heart valve 300may decouple from hub 440 as heart valve 300 fully expands, atraumatictip 430 may be retracted through heart valve 300 in the direction ofarrow S2 and delivery system 400 may be removed from the patient.

FIG. 5 shows a variation of the embodiment described above withreference to FIGS. 3A-4D. Heart valve 500 extends between proximal end502 and distal end 504 and includes stent 306 and a valve assembly 508having leaflets 510 and cuff 512. Stent 506 includes a plurality ofstruts 520 forming cells 522 and having retaining elements 521 at thedistal end of the heart valve as described above. Heart valve 500further includes projecting struts 530 disposed near proximal end 502.In contrast to heart valve 300 of FIGS. 3A-C, projecting struts 530 arecoupled to select struts 520 at locations remote from the nodes definedby intersecting struts. As shown, projecting struts 530 are coupled tothe proximal-most struts 520 a,520 b approximately halfway betweennodes. Each projecting struts 530 includes an eyelet 532 for couplingthe strut to cuff 512. In use, heart valve 500 functions similar toheart valve 300 and projecting struts may alternate between asubstantially parallel configuration for delivery to an angledconfiguration for sealing heart valve 500 within a native valve annulus.

Instead of projecting struts, additional rows of cells may be used toaid in paravalvular sealing. Stent 606 of FIGS. 6A-C illustrates onesuch embodiment. For the sake of clarity, a valve assembly (e.g., cuffand leaflets) is not shown in FIGS. 6A-C, though it will be understoodthat a valve assembly is coupled to stent 606 to form a functional heartvalve. Stent 606 extends between proximal end 602 and distal end 604.Stent 606 includes a plurality of first struts 620 forming cells 622 andhaving retaining elements 621 at the distal end of the stent fordelivery. Stent 606 may further include commissure features 625 to whichportions of the leaflets and/or cuff are attached. Stent 606 may includethree sections as previously described, including annulus section 640adjacent proximal end 602, aortic section 642 adjacent distal end 604,and transition section 641 between annulus section 640 and aorticsection 642. Commissure features 625 may be positioned entirely withinannulus section 640 or at the juncture of annulus section 640 andtransition section 641 as shown.

An additional sealing row 650 of cells is added to the proximal end 602of stent 606. Sealing row 650, in its fully expanded condition maydefine a diameter that is larger than the diameter of annulus section640 when stent 606 is expanded in the native valve annulus. Thus, asshown in FIG. 6B, the difference between the fully-expanded diameter d2of sealing row 650 and the fully-expanded diameter dl of annulus section640 may be between about 4.0 mm to about 6.0 mm. In other words, sealingrow 650 extends outwardly about 2.0 to 3.0 mm in each radial directionbeyond annulus section 640. The difference between the fully-expandeddiameter d2 of sealing row 650 and the fully-expanded diameter dl ofannulus section 640 may also be between about 2.0 mm to about4.0 mm.

The details of sealing row 650 will be discussed in greater detail withreference to FIG. 6C. As shown, stent 606 includes a row R1 ofdiamond-shaped cells 622 formed by intersecting first struts 630. Forexample, cell 622 a is formed by connecting first struts 630 a-d. Ablunt end 636 shaped as a horseshoe is formed at the intersection of thelowermost struts 630 (e.g., struts 630 c and 630 d of cell 622 a). Anadditional sealing row 650 is formed proximal to row R1 of cells 622.Sealing row 650 may generally include a number of deflecting cells 651,each deflecting cell 651 being formed of slender struts 652 that have athickness t2 that is smaller than the thickness t1 of first struts 630(FIG. 6D). In at least some examples, first struts 630 are twice asthick as slender struts 652. In at least some examples, first struts 630are formed with a thickness of about 0.25 to about 0.50 mm or about 0.40mm to about 0.50 mm, and slender struts are formed with a thickness ofabout 0.1 to about 0.2 mm or between about 0.15 mm to about 0.20 mm. Thereduced thickness of slender struts 652 may provide increasedflexibility and allow them to more readily bend to form outwardlyprojecting sealing row 650. Slender struts 652 further allow deflectingcells 651 to be conformable to patient anatomy as well as calciumnodules, if present.

Sealing row 650 of deflecting cells 651 may have a spring constant thatis less than the spring constant of annulus section 640. In other words,sealing row 650 may be made more conformable than annulus section 640.Annulus section 640 may be formed flexible enough to conform to thepatient's anatomy yet rigid enough to provide adequate anchoring of thevalve assembly within the native valve annulus. Conversely, deflectingcells 651 may provide little anchoring of the valve but are moreconformable to accommodate calcium nodules and the native anatomicalstructures, such as unresected leaflets in order to minimizeparavalvular leakage.

Deflecting cells 651 may be formed of two upper struts 653 a,653 b andtwo lower struts 654 a,654 b. Each of upper struts 653 are coupled atone end to nodes 631 of adjacent cells 622 and two lower struts 654a,654 b at the other end. In addition to being coupled to upper struts653 a,653 b respectively, lower struts 654 a,654 b are coupled to eachother. As schematically shown in FIG. 6B, upper struts 653 are angledoutwardly from annulus section 640 to define a second, larger diameterd2 of sealing row 650. Upper struts 653 may be about 9.0 mm to about10.0 mm in length. When implanted, a portion of stent 606 may extendbelow the native valve annulus and the length of upper struts 653 willbe partially responsible for the amount of deflecting cells 651 thatprotrudes below the annulus. Generally, the longer the upper strut, themore deflecting cell 651 will extend below the native valve annulus. Forexample, with a 9.0 mm length of upper struts 653, approximately 1.0 mmto 6.0 mm of deflecting cell 651 protrudes below the native valveannulus, depending on the overall geometry of cell 651.

Moreover, in addition to diameter, several factors may be modified inorder to form the desired shape for paravalvular leakage preventionincluding the lengths of struts 653,654 and the shape of deflectingcells 651. Such variations will be described in greater detail withreference to FIGS. 7-8.

FIGS. 7A-C illustrate a variation of stent 606 of FIGS. 6A-C. Stent 706extends between proximal end 702 and distal end 704 and includes aplurality of struts 720 forming cells 722 and having retaining elements721 at the distal end of the stent. Stent 706 may further includecommissure features 725 and may be divided into roughly three sectionsas previously described, including annulus section 740 adjacent proximalend 702, aortic section 742 adjacent distal end 704, and transitionsection 741 between annulus section 740 and aortic section 742. Anadditional sealing row 750 of deflecting cells 751 having an expandeddiameter as described earlier is formed.

The principle difference between stent 606 and stent 706 is in the shapeof defecting cells 751. Deflecting cells 751 may be formed of two upperstruts 753 a,753 b and two lower struts 754 a,754 b. Each of upperstruts 753 are coupled at one end to node 731 of adjacent cells 722 andtwo lower struts 754 a,754 b at the other end. In addition to beingcoupled to upper struts 753 a,753 b respectively, lower struts 754 a,754b are coupled to each other. Upper struts 753 may be formed of the samelength as upper struts 653 (e.g., about 9.0 mm to about 10.0 mm inlength). In order to reduce the portion of deflecting cells 651extending below the native valve annulus, lower struts 754 a,754 b maybe attached to upper struts 753 a,753 b at an angle β that is smallerthan the attachment angle of stent 606. In at least some examples, theangle β may be between about 90 degrees and about 145 degrees. In otherexamples, the angle β may be between less than 90 degrees or greaterthan 145 degrees. Additionally, lower struts 754 a,754 b may be slightlyshortened to accommodate this difference in attachment angle.

FIGS. 8A-C illustrate yet another variation of stent 606 and includesall the elements described with reference to FIGS. 6A-C. Like-numberedelements of FIGS. 6A-C correspond to like-numbered elements in FIGS.8A-C, but preceded by an “8” instead of a “6”. For example, cells 622 inFIG. 6A correspond to cells 822 in FIG. 8A. In contrast to upper struts653, upper struts 853 are shortened to reduce the portion of deflectingcells 851 extending past the native valve annulus. In this example,upper struts 853 are approximately 4 mm to 5 mm in length. Furtherreduction in length may be achieved by shortening upper struts 853,reducing the attachment angle as described with reference to FIGS. 7A-Cor removing the upper struts entirely such that the lower struts aredirectly attached to the nodes.

The preceding embodiments have illustrated several embodiments ofprojecting struts or deflecting cells capable of pushing a cuffoutwardly toward walls of the native valve annulus to seal a heart valvewithin the annulus. Several configurations of the cuff are also possibleas illustrated below. It will be understood that any of the followingconfigurations may be used in conjunction with any of the stentstructures described above.

FIGS. 9A and 9B are schematic views of a portion of heart valve 900including stent 906 with cuff 912 attached to same. For the sake ofclarity, leaflets of the valve assembly are not shown. Stent 906includes a plurality of struts 920 attached together to formdiamond-shaped cells 922. Three commissure features 925 a, 925 b, 925 care also shown attached to struts 920. Stent 906 further includessealing row 950 formed of a plurality of deflecting cells 951, eachdeflecting cell being formed of slender struts 952 as discussed above.

Cuff 912 is disposed on the abluminal surface of stent 906 (i.e., FIG. 9is a schematic illustration of the exterior of heart valve 900). Cuff912 may be formed of a polymer, a fabric or tissue, such as bovine,porcine, ovine, equine, kangaroo, PTFE, UHMWPE, PET, Dacron, PVA,Polyurethane, silicone or combinations thereof. In this configuration,cuff 912 is formed of three distinct fragments, F1, F2, F3 that are sewntogether to ease manufacturability, each fragment corresponding to oneof the commissure features 925. It will be understood, however, thatcuff 912 may be formed of one, two, three, four or more fragments.Moreover, fragments may be disposed vertically and/or circumferentially,may be formed of the same or different materials and any one orcombination of fragments may include other materials such as memoryshape materials. In use, when released from a delivery device,deflecting cells 951 radially expand and push external cuff 912 againstthe walls of the native valve annulus to seal heart valve 900 and reduceparavalvular leakage.

FIGS. 10A and 10B are schematic views of a portion of heart valve 1000including stent 1006 with cuff 1012 attached to same. Stent 1006includes a plurality of struts 1020 forming cells 1022 and commissurefeatures 1025. Stent 1006 further includes sealing row 1050 formed of aplurality of deflecting cells 1051, each deflecting cell being formed ofslender struts 1052 as discussed above. The main difference betweenheart valve 900 and heart valve 1000 is that cuff 1012 forms two layersL1, L2 on the abluminal surface. Specifically, a first layer L1 extendsfrom commissure features 1025 to proximal edge E1 of cuff 1012. The cuffis folded over away from stent 1006 to form a second layer L2. Pockets1060 may be formed between layers L1, L2.

As shown, pockets 1060 formed between layers L1, L2 of cuff 1016 mayinclude open edges E2. During use, blood flowing back toward theproximal end of the heart valve may fill pockets 1060 and expand thepockets to reduce the amount of paravalvular leakage. Alternatively,pockets 1060 may be filled with a liquid, a gel, a powder or other mediaand closed shut via sutures, adhesive or other known methods to mitigateparavalvular leakage. One example of the filler media may be a solutionof polyvinyl alcohol (PVA). As cuff 1012 contacts blood upon theimplantation of prosthetic heart valve 1000, the filler media may swellin size, increasing the size and specifically the diameter of thepockets between layers L1, L2. The enlarged pockets thus fill the gapsbetween the native valve annulus and the prosthetic heart valve,minimizing or preventing paravalvular leakage.

Though the previous embodiments have shown cuffs attached to theabluminal surface of stents (e.g., external surfaces), theconfigurations are not so limited. FIGS. 11A and 11B are schematic viewsof a portion of heart valve 1100 including stent 1106 with cuff 1112attached to same. Stent 1106 includes a plurality of struts 1120 formingcells 1122 and commissure features 1125. Stent 1106 further includessealing row 1150 formed of a plurality of deflecting cells 1151, eachdeflecting cell being formed of slender struts 1152.

In this configuration, cuff 1112 is divided into two fragments includingan upper portion 1112 a and a lower portion 1112 b. Upper portion 1112 amay be disposed on the luminal surface of stent 1106 and attachedthereto, spanning commissure features 1125, cells 1122 in row R1 thatare under commissure features 1125 and portions of cells 1122 in row R2.Lower portions 1112 b may be disposed on the abluminal surface andextend over the remaining portions of cells 1122 in row R2 and sealingrow 1150, covering deflecting cells 1151.

FIGS. 12A and 12B are schematic views of a portion of heart valve 1200including stent 1206 with wrap-around cuff 1212 attached to same. Stent1206 includes a plurality of struts 1220 forming cells 1222 andcommissure features 1225. Stent 1206 further includes sealing row 1250formed of a plurality of deflecting cells 1251, each deflecting cellbeing formed of slender struts 1252.

In this configuration, cuff 1212 is divided into an inner portion 1212 aand outer portion 1212 b. Inner portion 1212 a may be disposed on theluminal surface of stent 1206 and attached thereto, spanning fromcommissure features 1222 to proximal edge E1. Cuff 1212 may then bewrapped around deflecting cells 1251 and extend distally towardcommissure features 1222, forming an outer portion 1212 b disposed onthe abluminal surface of stent 1206. As shown, outer portion 1212 bterminates at edges E2, which may be sutured to inner portion 1212 a toform pockets 1260 containing filler media as described above.Alternatively, portions of edges E2 may be kept open so thatback-flowing blood enters pockets 1260 and causes the pockets to expandto reduce paravalvular leakage.

FIG. 13 is a highly schematic cross-sectional view showing heart valve1300 having stent 1302, valve assembly 1304 including leaflets 1308 anda cuff 1322, and deflecting cells 1330 supporting portions of cuff 1322.As seen in FIG. 13, deflecting cells 1330 extend radially outward fromstent 1302 to press cuff 1322 into the gaps between heart valve 1300 andnative valve annulus 1350. Cuff 1322 may be capable of promoting tissuegrowth between heart valve 1300 and native valve annulus 1350. Forexample, cuff 1322 may be innately capable or promoting tissue growthand/or may be treated with a biological or chemical agent to promotetissue growth, further enabling it to seal the heart valve within thenative valve annulus. When deflecting cells 1330 are functioningproperly, heart valve 1300 will be adequately sealed within native valveannulus 1350 so that blood flows through leaflets 1308 of valve assembly1304, and so that blood flow through any gaps formed between heart valve1300 and native valve annulus 1350 is limited or reduced.

While the devices disclosed herein have been described for use inconnection with heart valve stents having a particular shape, the stentcould have different shapes, such as a flared or conical annulussection, a less-bulbous aortic section, and the like, as well as adifferently shaped transition section. Additionally, though the stentsand cuffs have been described in connection with expandabletranscatheter aortic valve replacement, they may also be used inconnection with other expandable cardiac valves, as well as withsurgical valves, sutureless valves and other devices in which it isdesirable to create a seal between the periphery of the device and theadjacent body tissue.

Moreover, although the disclosures herein have been described withreference to particular embodiments, it is to be understood that theseembodiments are merely illustrative of the principles and applicationsof the present disclosure. For example, in embodiments having deflectingcells, it will be appreciated that each deflecting cell may be capableof independent movement, for example, by providing independent upperstruts for each deflecting cell. Deflecting cells also need not becontinuous around the perimeter of the annulus section. Instead, anumber of deflecting cells may be disposed around the circumference ofthe annulus section, each deflecting cell being spaced from adjacentones. Additionally, while the deflecting cells and projecting strutshave been shown as being disposed proximal to the annulus section of astent, such features may instead be disposed adjacent the annulussection or the transition section. Deflecting cells and projectingstruts may also be disposed proximal to the annulus section and extenddistally toward the aortic section. In other variation, the heart valveneed not include all of the section discussed above (e.g., the aortic ortransition sections may be eliminated entirely). It is therefore to beunderstood that numerous modifications may be made to the illustrativeembodiments and that other arrangements may be devised without departingfrom the spirit and scope of the present claims.

In some embodiments, a prosthetic heart valve for replacing a nativevalve includes a collapsible and expandable stent extending between aproximal end and a distal end. The stent includes an annulus sectionadjacent the proximal end and having a first diameter, a plurality offirst struts forming cells, and a plurality of second struts connectedto the annulus section and forming a plurality of deflecting cellsexpandable to define a second diameter larger than the first diameter. Avalve assembly is disposed within the stent and a cuff is coupled to thestent and covers the plurality of deflecting cells.

In some examples, each of the deflecting cells may include upper strutsand lower struts, the upper struts being joined to the lower struts atan angle of between about 90 degrees and about 145 degrees; and/or theheart valve may be implantable within a native valve annulus and aportion of the deflecting cells may be disposed below the native valveannulus when implanted; and/or the second diameter may be about 4.0 mmto about 6.0 mm larger than the first diameter in an expanded condition;and/or each of the deflecting cells may include upper struts and lowerstruts, the upper struts being about 9.0 mm to about 10.0 mm in length;and/or the first struts may have a first thickness and the second strutshave a second thickness, the first thickness being greater than thesecond thickness; and/or the first thickness may be twice as large asthe second thickness; and/or the cuff may be formed of multiplefragments; and/or the cuff may be at least partially disposed on anabluminal surface of the stent; and/or the cuff may include a firstlayer and a second layer, the first layer being disposed on theabluminal surface of the stent and extending from the plurality ofcommissure features to a proximal edge, the cuff being folded at theproximal edge away from the stent to form a second layer on the firstlayer; and/or the first layer and second layer may be sutured togetherto define a plurality of pockets open at second edges, the pockets beingconfigured to expand upon receiving back-flowing blood; and/or the cuffmay include a first portion disposed on an abluminal surface of thestent, and a second portion disposed on a luminal surface of the stent;and/or the stent may include a plurality of commissure features and thecuff extends from the plurality of commissure features to the proximaledge on an abluminal surface of the stent, and folds over the deflectingcells so that the second portion is disposed on the luminal surface ofthe stent.

In some embodiments, a prosthetic heart valve for replacing a nativevalve includes a collapsible and expandable stent extending between aproximal end and a distal end and an annulus section adjacent theproximal end and having a first diameter. The stent includes a pluralityof first struts forming cells, and a plurality of projecting strutsjoined to proximal-most cells, each of the projecting struts having afree end and an attached end joined to an intersection of first struts.A valve assembly is disposed within the stent and a cuff is coupled tothe stent and covering the projecting struts.

In some examples, each of the projecting struts may include an eyeletdisposed at the free end; and/or each of the projecting struts iscapable of independent movements from others of the projecting strutsand/or the projecting struts may be arranged in pairs, each two of theprojecting struts being attached to a same intersection of first struts;and/or the projecting struts may be angled between about 15 degrees andabout 35 degrees away from a longitudinal axis of the stent; and/or thecuff may be at least partially disposed on an abluminal surface of thestent; and/or the cuff may be at least partially disposed on a luminalsurface of the stent.

In some embodiments, a prosthetic heart valve for replacing a nativeheart valve includes a collapsible and expandable stent having proximaland distal ends, the stent including an annulus section adjacent theproximal end, the annulus section having a first expanded diameter and afirst radial spring constant. The stent further includes a plurality ofdeflecting features which project outwardly from the annulus sectionwhen the stent is in an expanded condition, the deflection featureshaving a lower radial spring constant than the first section. A valve isdisposed within the annulus section distal to the deflection features,the valve being operative to permit flow toward the distal end of thestent and to substantially block flow toward the proximal end of thestent. The heart valve further includes a cuff, a portion of the cuffbeing coupled to the deflection features.

It will be appreciated that the various dependent claims and thefeatures set forth therein can be combined in different ways thanpresented in the initial claims. It will also be appreciated that thefeatures described in connection with individual embodiments may beshared with others of the described embodiments.

1. A prosthetic heart valve for replacing a native valve, comprising: acollapsible and expandable stent extending between a proximal inflow endand a distal outflow end, the stent including an annulus sectionadjacent the proximal end and having a first diameter, a plurality offirst struts forming first cells, and a plurality of second strutsconnected to the annulus section and forming a plurality of second cellsexpandable to define a second diameter larger than the first diameter,the second cells being positioned nearer the proximal end than are thefirst cells; a valve assembly disposed within the stent; and a cuffcoupled to the stent and covering the plurality of second cells, thecuff including an abluminal portion disposed on an abluminal surface ofthe stent, and a luminal portion disposed on a luminal surface of thestent.
 2. The prosthetic heart valve of claim 1, wherein each of thesecond cells includes upper struts and lower struts, the upper strutsbeing joined to the lower struts at an angle of between about 90 degreesand about 145 degrees.
 3. The prosthetic heart valve of claim 1, whereinthe heart valve is implantable within a native valve annulus and aportion of the second cells is disposed below the native valve annuluswhen implanted.
 4. The prosthetic heart valve of claim 1, wherein thesecond diameter is about 4.0 mm to about 6.0 mm larger than the firstdiameter in an expanded condition.
 5. The prosthetic heart valve ofclaim 1, wherein each of the second cells includes upper struts andlower struts, the upper struts being about 9.0 mm to about 10.0 mm inlength.
 6. The prosthetic heart valve of claim 1, wherein the firststruts have a first thickness and the second struts have a secondthickness, the first thickness being greater than the second thickness.7. The prosthetic heart valve of claim 6, wherein the first thickness istwice as large as the second thickness.
 8. The prosthetic heart valve ofclaim 1, wherein the cuff is formed of multiple fragments.
 9. Theprosthetic heart valve of claim 1, wherein the stent includes aplurality of commissure features, the valve assembly being coupled tothe commissure features.
 10. The prosthetic heart valve of claim 9,wherein the luminal portion of the cuff extends from the plurality ofcommissure features to a proximal edge of the stent.
 11. The prostheticheart valve of claim 10, wherein the abluminal portion of the cuffextends from the proximal edge of the stent to a distal edge of theabluminal portion of the cuff.
 12. The prosthetic heart valve of claim11, wherein the luminal portion of the cuff and the abluminal portion ofthe cuff are continuous, the cuff folding over the second cells at theproximal edge of the stent.
 13. The prosthetic heart valve of claim 11,wherein the distal edge of the abluminal portion of the cuff is suturedto the luminal portion of the cuff to form pockets.
 14. The prostheticheart valve of claim 13, wherein the pockets are closed.
 15. Theprosthetic heart valve of claim 14, wherein the closed pockets arefilled with a filler material that swells upon contact with blood. 16.The prosthetic heart valve of claim 15, wherein the filler materialincludes polyvinyl alcohol.
 17. The prosthetic heart valve of claim 13,wherein the pockets include open edges so that the pockets areconfigured to fill upon retrograde flow of blood into the pockets. 18.The prosthetic heart valve of claim 13, wherein the abluminal portion ofthe cuff is formed of animal tissue.
 19. The prosthetic heart valve ofclaim 18, wherein the animal tissue is porcine tissue.
 20. Theprosthetic heart valve of claim 1, wherein the stent includes an aorticsection having a larger diameter than the annulus section.